If what you're trying to do is profile your app, use a profiling tool.

If you're trying to come up with some auditing mechanism whereby you can record every step your application took, don't mess with the compiler.

Why? Go look at how many bugs get filed against compilers. Now, look at who writes those compilers, and how many test cases the off-the-shelf compilers have to pass.

In other words, there are a good number of bugs, but the compilers are maintained by experts in the field AND the compilers are subject to not only the test cases the maintainers put their code through but also the testing done by everyone else using that compiler.

Now, you want to modify that compiler? How much testing are you going to put it through? Anywhere near what the standard compiler code base goes through?

And then your app is going to be completely dependent upon what's now your own private compiler?

Do you really want to mess with the application that translates your source code into machine language? How would you even know if you broke it?